Endoscope

This application is a Continuation of PCT International Application No. PCT/JP2022/005886 filed on 15 Feb. 2022, which claims priority under 35 U.S.C § 119(a) to Japanese Patent Application No. 2021-024398 filed on 18 Feb. 2021. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.

The present invention relates to an endoscope that changes a lead-out direction of a treatment tool.

Endoscopes for use in the medical field are used not only for observation of the inside of a subject but also for various treatments on an observation site. The endoscope includes an insertion part to be inserted into a subject and an operation part provided to be continuous with a proximal end portion of the insertion part. Various treatment tools, such as a forceps and an incision tool, are inserted into a treatment tool channel in the insertion part from a treatment tool lead-in port provided in the operation part of the endoscope and are led out of a treatment tool lead-out port opened at a distal end part of the insertion part, whereby various treatments, such as resection and collection of an observation site, are performed.

It is necessary to change a lead-out direction of the treatment tool to be led out from the treatment tool lead-out port of the endoscope in order to treat a desired position in the subject. Therefore, an elevating base that changes a lead-out direction of the treatment tool is provided at the distal end part of the insertion part. By operating an elevating operation lever provided on the operation part, a posture of the elevating base is moved between a fallen position and an elevated position. Moving the elevating base from the fallen position to the elevated position enables the elevating base to guide the treatment tool and change the lead-out direction of the treatment tool (see JP2020-137947A).

Additionally, in the endoscope recited in JP2006-015018A (corresponding to US2007/232857A1), a slit into which a guide wire is fit is formed in an elevating base. The guide wire is inserted into a treatment tool channel together with a treatment tool to guide the treatment tool. Then, in a case where the elevating base reaches an elevated position, the guide wire is fitted into the slit of the elevating base to fix the elevating base. As a result, an elevating operation lever that moves in conjunction with the elevating base is also fixed.

Meanwhile, in the endoscope recited in JP2011-072455A (corresponding to US2011/0077461A1), a friction resistance applying spring material is attached to an elevating operation lever. In a state of being pressed against a fixed wall formed on an operation part, the friction resistance applying spring material rotates integrally with the elevating operation lever. A lubricant is applied between the friction resistance applying spring material and the fixed wall. The friction resistance applying spring material is pressed against the fixed wall by an elastic force to generate frictional resistance. When a user releases his/her hand from the elevating operation lever, the elevating operation lever is temporarily stopped due to frictional resistance.

When a treatment is performed using an endoscope, a case may occur where a user wants to stop a lead-out direction of a treatment tool in a desired direction and perform the treatment with the lead-out direction maintained. Therefore, it is desired to stop an elevating base not only at an elevated position or a fallen position but also in the middle between the elevated position and the fallen position.

However, in the endoscopes recited in JP2020-137947A and JP2006-015018A, stopping the elevating base in the middle between the elevated position and the fallen position is not taken into consideration. In particular, in the endoscope recited in JP2006-015018A, the guide wire is fixed to stop the elevating base and the elevating operation lever only when the elevating base is at the elevated position, and cannot be fixed when the elevating base is at other positions. Furthermore, in this case, even if the elevating operation lever is pressed by a finger or the like, the elevating operation lever will be moved by a reaction force from the treatment tool.

Furthermore, in the endoscope recited in JP2011-072455A, although when the user releases his/her hand from the elevating operation lever, the elevating operation lever is temporarily stopped by frictional resistance between the friction resistance applying spring material and the fixed wall, and when a treatment is performed using a treatment tool having high rigidity, such as a stent or a puncture needle, the elevating operation lever receives too great a reaction force from the treatment tool to maintain a stopped state only with the frictional resistance. As a result, the elevating base is moved in conjunction with the elevating operation lever, so that the lead-out direction of the treatment tool also deviates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an endoscope capable of maintaining a lead-out direction of a treatment tool at a desired direction and performing various treatments while the lead-out direction is maintained.

An endoscope according to an aspect of the present invention includes an insertion part, an operation part, a distal end part main body, an elevating base, an elevating operation lever, a bearing member, a coupling member, and a locking mechanism, in which in a case where a protrusion is fitted to a hole, the elevating operation lever is locked at a first position, and in a case where the elevating operation lever is rotated in a first direction or a second direction, the protrusion passes through an elastically deformed rail and moves to a hole at a position different from the first position to lock the elevating operation lever at a second position. The insertion part is inserted into a subject. The operation part is provided at a proximal end of the insertion part. The distal end part main body is positioned at a distal end of the insertion part and communicates with a treatment tool lead-out port. The elevating base is an elevating base that is provided on the distal end part main body and that causes a treatment tool led out from the treatment tool lead-out port to elevate, and is provided to be movable between an elevated position and a fallen position. As the elevating operation lever rotates in a first direction, the elevating operation lever causes the elevating base to move to the elevated position, and as the elevating operation lever rotates in a second direction, the elevating operation lever causes the elevating base to move to the fallen position. The bearing member is provided in the operation part. The coupling member couples the elevating operation lever and the bearing member to each other. The locking mechanism is provided between the bearing member and the coupling member, and includes a plurality of protrusions, a plurality of holes, and a rail. The plurality of protrusions are provided on one of the bearing member and the coupling member. The plurality of holes are provided on the other of the bearing member and the coupling member. The rail is positioned between adjacent holes.

The holes and the protrusions are formed at the same pitch, and the number of the protrusions is smaller than the number of the holes. Preferably, one of the bearing member and the coupling member has the protrusions formed along a first arc positioned around a center axis, and the other of the bearing member and the coupling member has the holes formed along a second arc that is positioned around the center axis, that has a radius equal to a radius of the first arc, and that has an arc length longer than an arc length of the first arc.

It is preferable that an inner diameter of the hole is formed to gradually decrease from an intermediate portion of the second arc toward both ends of the second arc. It is preferable that the insertion part includes a bendable part, and an angle knob that curves the bendable part is attached to the bearing member.

It is preferable that at least some components are disposable.

According to the present invention, it is possible to provide an endoscope capable of maintaining a lead-out direction of a treatment tool at a desired direction and performing various treatments while the lead-out direction is maintained.

1 FIG. 10 12 13 14 15 16 17 12 14 15 10 16 17 As shown in, an endoscope systemincludes an endoscope, a treatment tool, a light source device, a processor device, a display, and a user interface (UI). The endoscopeimages an observation target. The light source deviceemits illumination light which illuminates the observation target. The processor deviceperforms system control of the endoscope system. The displayis a display part that displays an observation image or the like based on an endoscope image. The UIhas a keyboard, a mouse, a touch pad, a microphone, and the like, and receives input operation by a doctor as a user.

12 It is preferable that at least some of the components configuring the endoscopeare formed of a resin material, a rubber material, a metal material, or the like, and are discarded as disposable. In addition, in a case of a metal material, it is more preferable to form a component by means of metal injection molding.

12 14 15 12 18 19 18 18 18 18 18 19 19 18 18 a b c a b c The endoscopeis optically connected to the light source deviceand is electrically connected to the processor device. The endoscopehas an insertion partto be inserted into a subject and an operation partprovided at a proximal end of the insertion part. The insertion partincludes a flexible part, a bendable part, and a distal end partwhich are provided to be continuous in this order from the proximal end toward a distal end. By operating an angle knobof the operation part, the bendable partis curved. As a result, the distal end partfaces a desired direction.

2 FIG. 4 FIG. 19 19 19 19 19 19 19 13 13 19 41 18 b c d e a c c c. As shown in, the operation partis provided with an elevating operation lever, a treatment tool lead-in port, an air/water supply button, and a suction button, in addition to the angle knob. The treatment tool lead-in portis an inlet for inserting the treatment tool. The treatment toolinserted into the treatment tool lead-in portis guided to an elevating base accommodation part(refer to) of the distal end part

19 45 33 33 13 41 32 41 13 32 b By operating the elevating operation lever, a treatment tool elevating mechanismto be described later operates to rotate an elevating base. Rotation of the elevating basecauses an advancing direction of the treatment toolguided to the elevating base accommodation partto be curved and guided in a direction toward an opening windowC on an upper surface side of the elevating base accommodation part, thereby causing the treatment toolto be led out of the opening windowC.

19 42 31 19 18 18 31 d e d e 3 4 FIGS.and 3 4 FIGS.and When the air/water supply buttonis operated, air and water are supplied to an air/water supply tube (not shown) to jet air and water from an air/water supply nozzleprovided in a distal end part main body(refer to). In addition, when the suction buttonis operated, body fluids, such as blood, can be suctioned via a treatment tool channelfrom a suction port that also serves as a treatment tool lead-out port(refer to) disposed in the distal end part main body.

43 44 18 43 c An image sensor, an illumination optical system, and the like, which will be described later, are provided in the distal end part. The image sensoris preferably a charge-coupled device (CCD) image sensor, a complementary metal-oxide-semiconductor (CMOS) image sensor, or the like.

15 16 17 15 43 16 The processor deviceis electrically connected to the displayand the UI. The processor deviceperforms image processing and the like on an endoscope image captured by the image sensorand causes the displayto display the endoscope image.

18 13 18 18 31 19 19 d d c The treatment tool channelfor insertion of the treatment toolis disposed in the insertion part. The treatment tool channelhas one end connected to the distal end part main body, and the other end connected to the treatment tool lead-in portprovided in the operation part.

13 18 18 13 12 d The treatment toolis a treatment tool for an endoscope that is inserted into a subject together with the insertion partthrough the treatment tool channel. As the treatment tool, for example, a biopsy forceps, a snare, a stent, a puncture needle, a high-frequency treatment tool, an ultrasonic treatment tool, or the like is combined with the endoscope.

13 21 22 23 21 18 12 22 21 d The treatment toolincludes a flexible sheath, an operation wire (not shown), a distal end part, and an operation part. The flexible sheathis a tubular sheath formed of a flexible material, for example, a soft resin, and is inserted into the treatment tool channelof the endoscope. The operation wire is provided integrally with the distal end partand is inserted into the flexible sheath.

18 31 32 32 31 18 31 32 31 18 33 31 c c 3 4 FIGS.and 1 FIG. The distal end parthas the distal end part main bodyand a capas shown in, and is configured by attachment of the capto the distal end part main body. The configuration of the distal end partis not limited thereto, and the distal end part main bodyand the capmay be integrally fixed to each other so as not to be detached by a user. The distal end part main bodyis provided on a distal end side of the insertion part(refer to), and the elevating baseis provided at the distal end part main body.

12 18 18 34 35 36 18 12 18 13 31 34 33 42 c d d 3 4 FIGS.and 3 4 FIGS.and The endoscopeis a side-viewing endoscope used as, for example, a duodenoscope, and the distal end partshown inhas a configuration in the side-viewing endoscope.show the treatment tool channel, an elevating operation wire, a signal cable, and a light guidewhich are disposed inside the insertion partof the endoscope. The treatment tool channelguides the distal end part of the treatment toolto the distal end part main body. The elevating operation wireis an operation wire for performing operation of rotating the elevating base. Illustration of an air/water supply channel and the like connected to the air/water supply nozzleis omitted to prevent complication.

32 32 32 32 32 32 32 32 31 32 3 4 FIGS.and The caphas a distal end side sealed and formed to be substantially tubular, and has a peripheral surface portionA and an end surface portionB. The substantially rectangular opening windowC is formed in a part of the peripheral surface portionA. In the example shown in, the opening windowC is an opening portion notched from the peripheral surface portionA to the end surface portionB. Hereinafter, a center axis direction of the distal end part main bodyand the capwill be described as an X-axis direction, an up-down direction orthogonal to the X-axis direction will be described as a Z-axis direction, and a left-right direction orthogonal to both the X-axis direction and the Z-axis direction will be described as a Y-axis direction.

32 31 32 41 32 18 18 32 41 43 44 32 32 31 e d When the capis attached to the distal end part main body, the capcovers the elevating base accommodation partto be described later, and the opening windowC is opened toward the Z-axis direction. This allows the treatment tool lead-out portof the treatment tool channelto communicate with the opening windowC through the elevating base accommodation part. The image sensorand the illumination optical systemare exposed through the opening windowC. The capis coaxially attached to the distal end part main body.

32 18 31 32 31 32 32 31 c The capis made of an elastic material, for example, a rubber material such as fluororubber or silicone rubber, or a resin material such as polysulfone or polycarbonate. The configuration of the distal end partis not limited thereto, and the distal end part main bodyand the capmay be integrally fixed to each other so as not to be detached by a user. A convex-shaped engagement part (not shown) to be engaged with a groove-shaped engaged part (not shown) formed on the distal end part main bodyis provided on a proximal end side of the cap, and engaging the engagement part with the engaged part results in detachably attaching the capto the distal end part main body.

4 FIG. 31 37 38 39 31 38 39 37 38 39 41 33 38 39 41 As illustrated in, the distal end part main bodyhas a disk partand a pair of partition wall partsand. The distal end part main bodyis made of, for example, a resin material. The pair of partition wall partsandis provided to protrude from the disk partin the X-axis direction. These partition wall partsandare arranged so as to be opposed to each other in the Y-axis direction. In addition, the above-described elevating base accommodation partaccommodating the elevating baseis provided between the partition wall partand the partition wall part. The elevating base accommodation partis opened in the Z-axis direction.

41 18 18 33 13 18 33 41 40 34 40 34 33 22 13 18 e d e e. 4 5 FIGS.and The elevating base accommodation partcommunicates with the treatment tool lead-out portof the treatment tool channel. The elevating basecauses the treatment toolled out of the treatment tool lead-out portto elevate. The elevating baseis rotatably attached inside the elevating base accommodation partvia a rotation shaft member(refer to), and is movable between an elevated position (a position indicated by a chain double-dashed line) and a fallen position (a position indicated by a solid line). A distal end of the elevating operation wireis coupled to an end portion of the rotation shaft member. As the elevating operation wireis pushed and pulled, the elevating baserotationally moves from the fallen position to the elevated position. This enables change of a lead-out direction of the distal end partof the treatment toolled out to the treatment tool lead-out port

37 18 18 37 18 b b b The disk partis coupled to a distal end side of the bendable part. The bendable partis configured by covering an outer periphery of a structure having a plurality of rotatably coupled curved pieces with a tubular net body, a rubber outer skin, or the like. The disk partis fixed to a curved piece positioned on the most distal end side among the plurality of curved pieces constituting the bendable partby, for example, screwing or adhesion using an adhesive.

38 41 38 42 43 44 43 35 44 36 42 31 43 44 43 44 42 The partition wall partis disposed adjacent to the elevating base accommodation partin the Y-axis direction. The partition wall partincludes the air/water supply nozzle, the image sensor, and the illumination optical system. The image sensoris electrically connected to the signal cable, and the illumination optical systemis optically connected to the light guide. The air/water supply nozzleis provided at the distal end part main bodytoward the image sensorand the illumination optical system, and accordingly, the image sensorand the illumination optical systemare cleaned by air and water jetted from the air/water supply nozzle.

35 36 15 14 18 19 15 43 16 36 14 44 The signal cableand the light guideare respectively connected to the processor deviceand the light source devicethrough the insertion part, the operation part, a connector (not shown), and the like. The processor deviceperforms image processing and the like on an imaging signal acquired by the image sensorand causes the displayto display an observation image. The light guideis configured with an optical fiber cable or the like, transmits illumination light emitted from the light source device, and irradiates an observation target with the illumination light through the illumination optical system.

5 FIG. 7 FIG. 45 34 19 34 40 33 19 b b As illustrated in, the treatment tool elevating mechanismperforms operation of pushing and pulling the elevating operation wireaccording to rotational operation of the elevating operation lever. Pushing and pulling the elevating operation wirecauses the rotation shaft memberand the elevating basedescribed above to rotate. The elevating operation leveris operated with a thumb T (refer to).

6 FIG. 45 19 46 47 48 49 51 52 53 46 46 19 53 b b As illustrated in, the treatment tool elevating mechanismincludes the elevating operation lever, a rotation ring, a crank member, a guide tube, a coupling head, a slider, a fixed ring, and a bearing member. The rotation ringis formed in a cylindrical shape. The rotation ringis a coupling member that couples the elevating operation leverand the bearing member.

53 54 46 54 53 52 46 52 46 19 19 52 46 19 46 f 7 FIG. The bearing memberis provided with a rotation shaft. The rotation ringis coaxially and rotatably attached to the rotation shaft. The bearing memberand the fixed ringhold the rotation ring. The fixed ringsupports an outer peripheral surface of the rotation ringand is fixed to a case(refer to) configuring an exterior of the operation part. The fixed ringprevents the rotation ringfrom disengaging from the operation part. A coupling member is not limited to a cylindrical shape like the rotation ring.

19 46 55 47 19 47 47 49 51 49 34 51 48 48 19 b b f 7 FIG. The elevating operation leveris coupled to the rotation ring, for example, by screwing with a screw. One end of the crank memberis rotatably coupled to the elevating operation levervia a coupling pinA, and the other end of the crank memberis coupled to the coupling head. The sliderhas one end to which the coupling headis attached and the other end to which the elevating operation wireis coupled. The slideris slidably supported by the guide tube. The guide tubeis fixed to the case(refer to).

7 FIG. 7 FIG. 53 19 54 56 19 54 19 54 56 19 18 f a a a b As shown in, the bearing memberis fixed to the case. The rotation shaftis formed hollow. An attachment shaftof the angle knobis inserted into the rotation shaftand fixed thereto. As a result, the angle knobis attached to the rotation shaftvia the attachment shaft. In, illustration of an internal mechanism of the angle knob, a mechanism for curving operation of the bendable part, and the like is omitted in order to prevent complication.

47 51 19 34 19 45 19 33 19 19 33 b b b b b The crank memberand the sliderconvert the rotation caused by the operation of the elevating operation leverinto linear motion, i.e., into pushing and pulling operation of the elevating operation wire. As the elevating operation leverrotates in a counterclockwise direction (first direction) by means of the pushing and pulling operation of the treatment tool elevating mechanism, the elevating operation levercauses the elevating baseto move to the elevated position, and as the elevating operation leverrotates in a clockwise direction (second direction), the elevating operation levercauses the elevating baseto be moved to the fallen position.

8 FIG. 61 53 46 61 62 63 64 63 62 46 63 64 53 As illustrated in, a locking mechanismis provided between the bearing memberand the rotation ring. The locking mechanismhas a plurality of protrusions, a plurality of holes, and a railpositioned between the adjacent holes. The protrusionsare provided on the rotation ring, and the holesand the railare provided on the bearing member.

9 FIG. 46 46 46 46 62 46 52 46 46 53 46 47 62 46 As shown in, the rotation ringhas a large diameter partA, a small diameter partB provided to be continuous with the large diameter partA, and the plurality of protrusions. The large diameter partA is supported by the above-described fixed ring. The small diameter partB has an outer diameter smaller than that of the large diameter partA and is projected on a bottom surface side facing the bearing member. A part of the small diameter partB is notched so as not to interfere with the operation of the crank member. The protrusionis a columnar protrusion that protrudes from the bottom surface side of the small diameter partB.

10 FIG. 62 1 1 46 62 46 62 1 1 46 62 1 1 As illustrated in, the protrusionsare formed along a first arc CApositioned around a center axis CLof the rotation ring. The protrusionis a columnar protrusion that protrudes from the bottom surface side of the small diameter partB. The protrusionsare formed along the first arc CApositioned around the center axis CLof the rotation ring. The protrusionsare arranged on the first arc CAat equal pitches P.

11 FIG. 53 54 53 54 53 53 54 53 53 19 63 53 63 2 2 54 2 1 2 2 1 1 63 2 2 f As illustrated in, the bearing memberhas the rotation shaft, a support partA provided to be continuous with the rotation shaft, and a fixed pieceB. The support partA is disposed around the rotation shaftand is formed in a cylindrical shape. The fixed pieceB protrudes from an outer peripheral surface of the support partA, and is fixed to the caseby, for example, screwing. The holeis a through hole opened in a columnar shape from an upper surface of the support partA. The holesare formed along a second arc CApositioned around a center axis CLof the rotation shaft. The second arc CAhas a radius equal to that of the first arc CA, and the second arc CAhas an arc length Llonger than an arc length Lof the first arc CA. The holesare arranged on the second arc CAat equal pitches P.

2 63 1 62 62 63 62 63 62 63 62 63 The pitch Pof the holesis the same as the pitch Pof the protrusions, and the number of the protrusionsis smaller than the number of the holes. Although in the present embodiment, the number of the protrusionsis seven and the number of the holesis ten, the numbers of the protrusionsand the holesare not limited thereto, and the number of the protrusionsneed only be smaller than the number of the holesby at least one.

63 62 63 62 64 63 2 64 62 64 62 64 62 62 64 62 19 64 62 64 62 b The holeis formed to have an inner diameter in accordance with an outer diameter of the protrusion, whereby the holeand the protrusionare fitted to each other. The railis disposed between the holesalong the second arc CA. When the railis not pressed by the protrusion, a width W of the railis smaller than the outer diameter of the protrusion. Accordingly, when the railis not pressed by the protrusion, the protrusionis not allowed to pass through the rail. In other words, the movement of the protrusionis restricted. Meanwhile, when the elevating operation leveris rotationally operated, the railis elastically deformed by pressing received from the protrusion. In other words, the railbecomes wider than the above-described width W. This allows the protrusionto move.

12 FIG.A 12 12 FIGS.A toC 62 63 64 19 62 63 62 63 62 b As shown in, when the protrusionis fitted to the hole, the movement of the protrusion is restricted by the railas described above. In other words, the elevating operation leveris locked at the first position. A state in which the protrusionis fitted to the holehere represents a state in which each protrusionis fitted to any one of the holes. Note thatare views for explanation focusing only on one protrusion, and are different from the actual configurations.

12 FIG.B 12 FIG.C 19 64 62 62 62 64 63 19 b b As shown in, when the elevating operation leveris rotated counterclockwise or clockwise, the railis elastically deformed by the pressing force received from the protrusion. As described above, the protrusionis allowed to move. As illustrated in, the protrusionpasses through the elastically deformed railand moves to the holeat a position different from the first position, and the elevating operation leveris locked at the second position.

62 63 33 62 63 19 13 62 63 33 33 31 33 13 12 33 62 63 b A fitting strength between the protrusionand the holein a case where the elevating baseis at the elevated position needs to be high enough to prevent the protrusionfrom detaching from the hole, i.e., to prevent the elevating operation leverfrom moving even when a reaction force is received from the treatment tool. In addition, it is preferable that the fitting strength between the protrusionand the holein a case where the elevating baseis at the fallen position is also a high fitting strength equivalent to that in the case where the elevating base is at the elevated position. That is, in a case where the elevating baseis rotated from the elevated position to the fallen position, the elevating base tends to rotate in a direction of returning to the elevated position due to a reaction force received by the distal end part main body. If the reaction force is so strong that the elevating baserotates to the elevated position, the treatment toolmight enter an observation range of the endoscopein a situation not intended by a user. Therefore, it is preferable that even in the case where the elevating baseis at the fallen position, the fitting strength between the protrusionand the holehas a high fitting strength equivalent to that in the case where the elevating base is at the elevated position.

13 FIG. 63 2 21 22 20 63 20 2 21 22 63 21 22 62 63 21 22 2 62 63 As illustrated in, the inner diameter of the holeis formed to gradually decrease from an intermediate portion of the second arc CAtoward both ends CAand CA. In the present embodiment, an inner diameter Rof the holeclosest to a center CAin a circumferential direction of the second arc CAis the largest, and inner diameters Rand Rof the holespositioned at both the ends CAand CAare the smallest. Accordingly, when the protrusionsare fitted to the holespositioned at both ends CAand CAof the second arc CA, the protrusionsare least likely to be detached from the holes.

63 21 22 2 62 19 33 63 21 22 2 62 33 62 63 b The holeslocated at both ends CAand CAof the second arc CAand the protrusionsare fitted to each other at both ends of a range in which the elevating operation leveris rotatable. In other words, in a case where the elevating baseis at the fallen position or the elevated position, the holeslocated at both ends CAand CAof the second arc CAand the protrusionsare fitted to each other. Therefore, in the case where the elevating baseis at the fallen position or the elevated position, the protrusionsare least likely to be detached from the holes.

13 18 12 18 12 13 18 19 13 18 18 33 13 13 43 19 33 13 d d c d e b Description will be made of operation which is performed by a doctor as a user when inserting the treatment toolinto the treatment tool channelof the endoscopeand conducting treatment on a patient as a subject. The doctor inserts the insertion partof the endoscopeinto a body of the patient. Furthermore, the treatment toolis inserted into the treatment tool channelthrough the treatment tool lead-in port. The treatment toolinserted into the treatment tool channelis led out of the treatment tool lead-out portinto the subject. In the case where the elevating baseis at the fallen position, the treatment toolis not elevated at all. In this case, the treatment toolis not present in the observation range imaged by the image sensor. For example, the doctor rotationally operates the elevating operation leverto move the elevating basefrom the fallen position to the elevated position in order to make the treatment toolenter the observation range.

12 61 19 62 63 19 13 64 62 62 62 64 63 19 19 33 61 13 13 22 13 43 b b b b As described above, since the endoscopeincludes the locking mechanism, the elevating operation leveris locked when the protrusionis fitted to the hole. Then, when the doctor rotationally operates the elevating operation leverin the counterclockwise direction in order to elevate the treatment tool, the railis elastically deformed by the pressing force received from the protrusionto allow the protrusionto move. Then, the protrusionpasses through the railto move to the different hole, so that the elevating operation leveris locked. In this manner, the doctor rotationally operates the elevating operation leverto rotate the elevating base, and the locking mechanismoperates. As a result, a lead-out direction of the treatment toolcan be changed to a desired direction. For example, the doctor determines that the lead-out direction of the treatment toolis changed to a desired direction when the distal end partof the treatment toolenters the observation range imaged by the image sensor.

13 33 19 62 19 19 13 13 19 33 13 22 13 32 b b b b As described above, when the doctor changes the lead-out direction of the treatment toolin a desired direction, the elevating basemay be at a position in the middle of the fallen position and the elevated position. In this case, the doctor stops the rotational operation of the elevating operation lever. This also makes the movement of the protrusionstop, so that the elevating operation leveris brought into a locked state. Since the elevating operation leveris locked, the doctor can perform treatment in a state where the lead-out direction of the treatment toolis maintained at the desired direction. Even if a treatment is performed in this state and a reaction force is received from the treatment tool, the elevating operation leverwill not move. As a result, the elevating basedoes not move either, and the lead-out direction of the treatment toolwill not deviate. By leading the distal end partof the treatment toolled out from the opening windowC in a state in which the lead-out direction is maintained at the desired direction, the doctor can perform various treatments such as resection and collection of an observation site.

33 13 18 22 19 13 33 34 45 33 33 33 34 45 63 2 62 63 33 13 19 33 d b b Additionally, when the elevating baseis at the elevated position, the treatment toolin many cases moves forward and backward in the treatment tool channelto perform the operation of the distal end part. In this case, as described above, the elevating operation leverreceives the largest reaction force from the treatment toolthrough the elevating base, the elevating operation wire, the treatment tool elevating mechanism, and the like. Furthermore, even in the case where the elevating baseis at the fallen position, since the elevating basetends to rotate due to the received reaction, the elevating operation lever receives a large reaction force through the elevating base, the elevating operation wire, the treatment tool elevating mechanism, and the like. Meanwhile, in the present invention, since the holeis formed to have the inner diameter that gradually decreases from the intermediate portion of the second arc CAtoward both ends, the protrusionis least likely to be detached from the holewhen the elevating baseis at the fallen position or the elevated position. Therefore, for example, even when the treatment toolhaving a large reaction force such as a stent or a puncture needle is used, the position of the elevating operation leverwill not deviate when the elevating baseis at the elevated position or the fallen position.

33 13 33 61 19 13 b Although the above embodiment illustrates, as an example, a case where the elevating baseis rotated from the fallen position toward the elevated position to direct the treatment toolin a desired direction, the present invention is not limited thereto, and even in a case of rotating the elevating basefrom the elevated position toward the fallen position, the locking mechanismoperates to lock the elevating operation leveras in the above embodiment. Then, various treatments can be performed while the lead-out direction of the treatment toolis maintained at a desired direction. Although the above embodiment illustrates, as an example, a case where the first direction is set as the counterclockwise direction and the second direction is set as the clockwise direction, the first direction may be set as the clockwise direction and the second direction may be set as the counterclockwise direction.

62 46 63 64 53 63 64 46 62 53 Furthermore, although in the above-described embodiment, the protrusionis provided on the rotation ringas the coupling member, and the plurality of holesand the railare provided on the bearing member, the present invention is not limited thereto, and the plurality of holesand the railmay be provided on the rotation ring, and the protrusionmay be provided on the bearing member.

10 : Endoscope system 12 : Endoscope 13 : Treatment tool 14 : Light source device 15 : Processor device 16 : Display 17 : User interface (UI) 18 : Insertion part 18 a : Flexible part 18 b : Bendable part 18 c : Distal end part 18 d : Treatment tool channel 18 e : Treatment tool lead-out port 19 : Operation part 19 a : Angle knob 19 b : Elevating operation lever 19 c : Treatment tool lead-in port 19 d : Air/water supply button 19 e : Suction button 19 f : Case 21 : Flexible sheath 22 : Distal end part 23 : Operation part 31 : Distal end part main body 32 : Cap 32 A: Peripheral surface portion 32 B: End surface portion 32 C: Opening window 33 : Elevating base 34 : Elevating operation wire 35 : Signal cable 36 : Light guide 37 : Disk part 38 : Partition wall part 39 : Partition wall part 41 : Elevating base accommodation part 42 : Air/water supply nozzle 43 : Image sensor 44 : Illumination optical system 45 : Treatment tool elevating mechanism 46 : Rotation ring 46 A: Large diameter part 46 B: Small diameter part 47 : Crank member 47 A: Coupling pin 48 : Guide tube 49 : Coupling head 51 : Slider 52 : Fixed ring 53 : Bearing member 53 A: Support part 53 B: Fixed piece 54 : Rotation shaft 55 : Screw 56 : Attachment shaft 61 : Locking mechanism 62 : Protrusion 63 : Hole 64 : Rail 1 CL: Center axis 2 CL: Center axis 1 CA: First arc 2 CA: Second arc 20 CA: Center 21 CA: End portion 22 CA: End portion 1 L: Arc length 2 L: Arc length